1. Sealant Backing
- Choose the appropriate sealant backing based on the available joint depth. Sealant backing will prevent three-sided adhesion, control sealant depth, and allow for tooling to ensure proper sealant / substrate contact.
- Foam cylindrical backer rod is typically installed and should be approximately 25% larger than the width of the joint to ensure a tight compressed fit. Three types are currently available: open cell, closed cell and hybrid. Consult the sealant manufacturer for the recommended backer rod type
- In joints where depth is not adequate to acept a backer road, a polyethylene bond breaker tape should be installed.
Refer to Pecora Technical Bulletin #106 Backer Rod Use for more information.
2. Sealant Mixing (multi-component sealants only)
- If a sealant requires mixing in the field, ensure that the manufacturer’s published mixing procedures are strictly followed.
- Thorough and uniform mixing is vital when installing multi-component sealants. Be sure to utilize the correct mixing equipment as recommended by the sealant manufacturer.
3. Sealant Dimensions
- The correct sealant dimensions are critical when installing joint sealants and will ensure the sealant maintains its designed performance characteristics.
- Width of joint to depth of sealant should be two to one (2:1) with no joint depth being less than ¼”.
4. Sealant Installation
- All sealing should be done when temperatures are above 40°F. Preferably, sealants should be installed at a median temperature and not at temperature extremes (low and high).
Refer to Pecora Technical Bulletin #65 Caulking at Low Temperatures for more information.
- All surfaces receiving sealant should be DRY and CLEAN.
- Sealant should be applied in a continuous operation using a professional grade cartridge-type caulking gun or bulk loading gun.
- Joints should be filled uniformly to the required sealant depth. Sealants may be recessed if required by manufacturer.
5. Tooling of Sealant
- Tool the sealant with light pressure to spread the material against the sealant backing and joint surfaces. Use a tool with a rounded tip to keep a concave sealant profile in the joint and maintain the industry standard “hourglass” configuration.
- The sealant should be dry tooled unless the sealant manufacturer specifically approves otherwise. If approved, the tool may be dampened with a sealant manufacturer approved tooling agent (typically mineral spirits).
- Do not use water or soapy water as a tooling agent. Avoid over tooling.
- Tool the sealant at window sills and similar places so that precipitation, cleaning solutions, etc. will not pond.
- Any masking materials used are to be removed immediately after tooling while the sealant is still in its uncured state (wet).
NOTE: All remedial sealant installations should be verified for proper performance through field adhesion testing.
Refer to Pecora Technical Bulletin #55 Field Adhesion Test Methods and Test Log for more information.
Refer to Pecora Technical Bulletin #108 Sealant Application Guide for additional application information.
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